In 1969, the Historic American Engineering Record (HAER) was established to document the achievements of engineers, industrialists, and laborers. Over the past 30 years, HAER has been the primary catalyst to ensure that engineering structures and the industrial workplace are documented through measured drawings and photographs and, when possible, preserved along with historic sites.
"Preservation through documentation" has been the modus operandi as HAER has worked to record America`s industrial, engineering, and technological achievements of historical significance. Some of the sites recorded serve as the foundation for subsequent preservation efforts that transform communities and the way people think about industrial workplaces. Steel mills, factories, foundries and the canal, road, and rail infrastructure that linked them together and to their larger markets now are beginning to be thoughtfully regarded and preserved with new insights.
Documenting Historic Bridges
Bridges form an important part of HAER`s collection with more than 1,000 recorded. These include the obvious icons such as the Brooklyn Bridge in New York, the Eads in St. Louis, and San Francisco`s Golden Gate Bridge. Equally significant are the more common types such as the iron trusses and concrete arches that adorn the American landscape. Thousands of these bridges were built, especially in the years following the Civil War when the rail-roads opened up the Midwest and West catapulting America into a process of infrastructure expansion and improvement that continues to this day. This burgeoning nation, coursed by dozens of rivers, thousands of creeks and streams, and millions of acres of swamps and coastal wetlands, was precluded from any physical union until the daunting impenetrability arising from the constant intervention of water was bridged by the engineer and builder.
No country in the world needed bridges like the United States. Transportation infrastructure first took the form of turnpikes, then canals, and eventually railroads-hundreds of lines. Once the frontier opened, settlers began building a matrix of farm-to-market roads, which required bridges by the thousands. The solution was "catalog bridges" -primarily iron trusses fabricated during the late-19th and early-20th century by numerous bridge companies and sold to local bridge commissions through catalogs. Americans depended on these little bridges to tie their communities together and link them to larger cities.
During early decades of the 20th century, single and multiple span concrete arches began to compete with metal trusses. Surprisingly, many of these bridges remain, with some still carrying traffic. Many of these bridges have passed the century mark, and some are starting to wear out.
Concern about the condition of the country`s bridges first arose following the worst bridge disaster in modern history-the collapse of the Silver Bridge over the Ohio River at Point Pleasant, W.Va., in 1967. Forty-six lives were lost.
In 1975 the General Accounting Office issued a report on unsafe bridges that generated further attention, especially by the media, on the issue of bridge safety. The New York Times followed up with article entitled "32,000 Old Bridges Termed Unsafe," which alerted Americans to the condition of the country`s decaying bridges. The Times article also signaled concern about the future of America`s historic bridges. Massive federal and state programs to upgrade the primary and secondary road system doomed older bridges. The nation stood to lose, in a single generation, the physical evidence of some of America`s greatest engineering and manufacturing achievements -the fabricated metal truss and the reinforced-concrete arch bridge.
Soon after the early bridge replacement programs started in the mid 1970s HAER staff initiated a series of symposiums and meetings to educate highway officials, engineers, preservationists, and the general public about the value and significance of older bridges. First coordinated with the state historic preservation offices, the Advisory Council on Historic Preservation, and the National Trust for Historic Preservation, these efforts soon expanded to include highway officials and engineers. For many years, preservationists were at logger-heads with highway officials and engineers over the bridge issue but this adversarial relationship subsided when it became apparent that the two groups had to work together if there was any hope of saving America`s historic bridges.
One of the first efforts of HAER and its partners was to promote the concept of comprehensive statewide historic bridge inventories. These efforts were largely successful. Just about every state has inventoried bridges not only for structural sufficiency and essentialness for public use but also for historical significance (Note 1). These inventories have led to listing or determinations of eligibility for listing of approximately 8,000 bridges in the National Register of Historic Places.
Today, however, preservationists and highway officials are asking a more complicated question: Now that we have identified all these bridges, what should we do with them? While no one advocates that every historic bridge should be saved, few can argue against preserving the outstanding and representative examples of different types of bridges.
Some can be rehabilitated for continued vehicular use, while others may need to be moved to new locations where the use and weight limits are not so critical. Some bridges may need to be bypassed completely. The best option and the one that should be most vigorously pursued is to keep these bridges in service so they stay eligible for state funding for maintenance and repairs. Bypassing a bridge should be a last resort, since it removes a bridge from the state inventory and the bridge slowly deteriorates from lack of maintenance.
When continued vehicular service is not possible, there are a number of alternatives where historic bridges have been saved by relocating them to hiking or biking trails or to backcountry roads in state, municipal or federal parks or wildlife refuges. Leaving old bridges for fishermen is one of the most popular and easiest adaptive uses. Historic bridge management or preservation plans in each state will help insure that these preservation options are considered. By the mid 1980s, as the first historic bridge inventories were being concluded, HAER began developing partnerships with some states by recording a selection of that state`s historic bridges identified by the inventories. Since then, bridges in ten states have been recorded, Ohio being the first in 1986 9Note 2).
Paralleling the state bridge-recording program, HAER started documenting bridges within the National Park system beginning with a pilot project in summer 1988 (Note 3). The roads and bridges within the national parks are subject to the same deterioration as those on primary and secondary roads but, because they are in national parks, HAER was particularly concerned that the bridges be rehabilitated in keeping with their original design intentions and character. A few years after the bridge documentation project in the national parks, HAER broadened its scope to include the landscape and natural features such as view sheds, historic vistas, and plant materials that are so critical to the public`s enjoyment and often the very reason for their designation as national parks. The culmination of the first 10 years of park projects was an exhibition, "Lying Lightly on the Land: Building America`s National Park Roads and Parkways," that ran for eight months at the National Building Museum in Washington.
Parkways and Scenic Byways
HAER has also turned its attention to parkways and scenic byways. The program has received funding to document historic parkways such as the Merritt in Connecticut, the Columbia River Gorge in Oregon, the Arroyo-Seco in Los Angeles and the Taconic in New York. All four have been disfigured over the years by insensitive upgrades to allow for higher speeds and increased commuter traffic, by poor maintenance, and, in some cases, by partial abandonment or overbuilding. HAER drawings served as baseline information for the maintenance crews and planners and were used in developing new rehabilitation guide-lines and interpretive programs for both the Merritt Parkway and the Columbia River Gorge Scenic Highway. The presence of HAER teams in the summer and the results of their work-drawings, photographs, and histories-made both the public and transportation officials aware of these historic resources.
HAER documentation not only provides specific information on the physical features, but also explains how the road is integrated into the landscape. The drawings and photographs make a compelling argument of how roads enhance the quality of life in our communities and the character of the countryside and cultural landscape.
Educating the Engineers
Preserving our roads and bridges requires the technical expertise of engineers. However, engineers and engineering educators interested in our engineering past are rare. There are many reasons for this but the one most critics point to is the fact that little in engineering education pre-pares students to deal with issues such as aesthetics, much less the concepts of cultural landscapes, preservation or, for that matter, restoring historic bridges. Some engineering educators have told me that course requirements are already overloaded just to get across the basics of sound engineering. Anything having to do with aesthetics or similar issues must be found outside the engineering curriculum and, most likely, on the student`s own time.
Unlike architectural curriculums that require at least a semester of architectural history, only a few engineering schools offer anything pertaining to aesthetics, the history of engineering, or the humanities. Consequently, it has been difficult to involve student engineers in the Historic American Engineering Record.
In its early years, HAER tried hiring engineering students on its summer teams but found that engineers had limited skills in producing drawings, photographs, or histories. Furthermore, while most engineering students understand structural behavior and are familiar with the latest computer programs to analyze modern bridges, rarely do they have the background or experience to analyze historic bridges. Pinned connections, built-up sections, and archaic materials such as cast and wrought iron were not taught in building material and structural engineering classes.
As Dario Gasparini, professor of civil engineering at Case Western Reserve University explained: "Most practicing engineers would be hard pressed to answer exactly how old bridges behave much less where to get information on such archaic materials as cast and wrought iron, early steels, and reinforced concrete." In 1996 Professor Gasparini, who has studied the history of bridges and their engineering, accepted my offer to work with the HAER teams. Under his guidance, carefully selected civil engineering students analyzed historic bridges using contemporary structural programs yet, at the same time, taking into consideration the original parameters under which the bridges were designed and built.
The engineering students added a new dimension to HAER`s historic bridge documentation program. For the first time we were able to say exactly how the bridges were working and reach some conclusions about which bridges were particularly innovative and well designed. I am convinced that in the same way that architects have become seminal to the preservation of historic buildings, engineers will do the same for historic bridges.
More and more bridges are going to be rehabilitated than replaced and several insightful engineering firms already are beginning to stake out expertise in historic-bridge rehabilitation as a part of their everyday practice (Note 4). Even with the billions available from TEA-21, the current surface transportation bill funding road and bridge projects, there is not enough money in the treasury-federal, state or local-to replace the estimated 250,000 structurally-deficient and functionally-obsolete bridges.
One intriguing lesson learned from our study of park roads was that the close cooperation between engineers and landscape architects pioneering early road and bridge systems resulted in functional and graceful bridges and roadways. National Park Service landscape architects and Bureau of Public Roads engineers developing the first paved roads in the national parks worked closely together to perfect these systems. Engineering journals and periodicals published lively discussions about design standards and aesthetics appropriate for road and bridge design. I would like to see a return to this interdisciplinary approach -landscape architects, engineers, historians, and preservationists working together, not necessarily on every project, but certainly the important ones.
Highway officials and bridge engineers have been maligned since the beginning of the interstate era as insensitive to historic bridges, the environment, and the cultural landscape. The vast sums of money allocated to transportation departments is indicative of the power they hold in state and federal governments. However, not all road officials and bridge engineers are evil. Times have changed significantly since the mid 1970s when HAER`s historic bridge program started. Many highway departments are now watching out for environmentally sensitive areas and historic resources. Engineers are becoming interested in their state`s historic bridges. The interstate era is over, and never again will there be the need to build new roads and bridges on the same scale of the last 40 years. Although new bridges will continue to be built, the rehabilitation of historic bridges is taking priority in some states (Note 5).
It is possible to bring additional excellence to America`s already superb highways by combining new construction while at the same time maintaining that which represents the very best handed down to us from the past so we can pass it on to the future. Saving historic roads and bridges of fine materials, humanly-scaled proportions, notable craftsmanship, and varied textures enhances the quality of life and maintains familiar surroundings. In places where it is perceived that historic architectural and cultural resources are lacking, attitudes supporting good design may also be absent. Such values are especially needed in America where we tend to throw away the past, build the expedient, pursue the quick profit and, in the process, trash the countryside. In this age of instant gratification, historic roads and bridges provide a link with the past as well as deeper insights and hope for the future (Note 6).
- For a review of the early era of bridge preservation in the United States, see William P. Chamberlin, National Cooperative Highway Research Program Synthesis of Highway Practice 101: Historic Bridges- Criteria for Decision Making, Transporta-tion Research Board, National Academy of Sciences, Washington, D.C., October 1983. A sequel, NCHRP Synthesis of Highway Practice 275: Historic Highway Bridge Preservation Practices, also written by William P. Chamberlin, is intended to complement NCHRP Synthesis 101 and was published by the National Research Board, National Academy of Sciences, Washington, D.C., in 1999.
- Following Ohio was New York and Wisconsin in 1987, Arkansas in 1988, Massachusetts and Oregon in 1990, Washington in 1993, Iowa in 1995, Texas and Iowa-II in 1996, Pennsylvania in 1997, and Pennsylvania-II in 1998, the Willamette River bridges in Portland, Oregon, and the Chicago River bridges in 1999. Texas-II and Merrill Butler`s collection of "City Beautiful" bridges and viaducts linking the downtown with East Los Angeles spanning the Los Angeles River are scheduled for recording in summer 2000. As an adjunct to the statewide recording projects, HAER initiated a special project, in cooperation with West Virginia University`s Institute for the History of Technology & Industrial Archaeology (IHTIA), to record the estimated 70 surviving cast and wrought-iron truss bridges, a special category of bridge type built between the end of the Civil War and the introduction of steel in the late 1890s. See Eric DeLony, "Surviving Cast and Wrought Iron Bridges in America," IA: The Journal of the Society for Industrial Archeology, Vol. 19, No. 2, 1993, p. 17-47.
- After a pilot survey in Washington that documented a variety of bridges in area parks, the program moved on to Yellowstone in 1989, the Going-to-the-Sun Road in Glacier in 1990, Yosemite in 1991, Mount Rainier in 1992, the General`s Highway in Sequoia and Zion Nation-al Park in 1993, Acadia, Grand Canyon, and Mesa Verde in 1994, Acadia-II, Colonial and Rock Creek Parkway in 1995, Great Smokey Mountains in 1996, Blue Ridge, Natchez Trace, and Vicksburg in 1997, Natchez Trace-II, Chickamauga/ Chattanooga, Shiloh, and Gettysburg in 1998, and Baltimore-Washington and Taconic in 1999. Roads and bridges in Scott`s Bluff National Monument (Neb.), Wind Cove National Park (S.D.), the landscape features associated with the Going-to-the-Sun Road in Glacier National Park, Rocky Mountain National Park, Redwood National Park, Lassen Volcanic National Park, and the Petrified Forest are scheduled for recording during 2000.
- The American Society of Civil Engineers continuing education department offered two courses on historic bridge rehabilitation in 1999, one in Boston and another in Chicago.
- Vermont is a good case in point. In 1996, the Vermont legislature passed precedent-setting legislation establishing as policy, the rehabilitation rather than replacement of bridges on state and local roads for the purpose of preserving the magical image that most people have of Vermont: largely an agrarian landscape accented by exquisite New England towns organized around beautiful town greens. This landscape is also a money maker. Thousands visit Vermont every year for the pleasure of experiencing this landscape, and the permanent residents appreciate the quality of life this scale of development and road construction affords. In recognition of this unprecedented effort, the Vermont Agency for Transportation won a National Preservation Award from the National Trust in 1997.
- In recognition of its efforts in promoting the preservation of historic bridges over the last 25 years, HAER received two prestigious awards: the President`s National Historic Preservation Award, sponsored by the Advisory Council on Historic Preservation under auspices of the White House in 1991, and the Design for Transportation National Awards, sponsored by the U.S. Department of Transportation and the National Endowment for the Arts, in 1995.